Datisca cannabinaCHAPTER XVIII. Colouring Matters of Unknown Constitution. (Osa artikkelista)

The Natural Organic Colouring Matters
By
Arthur George Perkin, F.R.S., F.R.S.E., F.I.C., professor of colour chemistry and dyeing in the University of Leeds
and
Arthur Ernest Everest, D.Sc., Ph.D., F.I.C., of the Wilton Research Laboratories; Late head of the Department of Coal-tar Colour Chemistry; Technical College, Huddersfield
Longmans, Green and Co.
39 Paternoster Row, London
Fourth Avenue & 30th Street, New York
Bombay, Calcutta, and Madras
1918

Kaikki kuvat (kemialliset kaavat) puuttuvat // None of the illustrations (of chemical formulas) included.

This is a tall, erect herb, resembling hemp, belonging to the Datisceæ, and met with in the temperate and sub-tropical Western Himalayas from Kashmir to Nepal. The root, known as Akalbir, has been extensively used in Kashmir and throughout the Himalayas as a yellow dyestuff chiefly on alum-mordanted silk; but the colouring matter appears to be present in the whole plant, for the leaves and twigs can also be employed for the same purpose.

The leaves of the Datisca cannabina were first examined by Braconnot (Ann. Chim. Phys., [2], in., 277), who isolated from them a crystalline substance which he named datiscin. Somewhat later it was shown by Stenhouse (Annalen, 1856, 98, 167) that this compound is a glucoside, and when hydrolysed is converted into a sugar, together with a yellow colouring matter, datiscetin, C₁₅H₁₀O₆.

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The dyeing properties of datisca root on wool are very similar to those of old fustic. It is, however, slightly inferior in dyeing power. On cotton it dyes more like quercitron bark, in so far that the olives obtained on iron mordant are bluer in shade, as though some tannin matter were present. It appears to have about the same colouring power as quercitron bark, but gives a brighter yellow with aluminium mordant. Applied to wool, it differs from quercitron bark by giving with chromium mordant an olive-yellow, which is not of such a reddish tinge, and with tin mordant a bright yellow instead of an orange. It is an excellent dyestuff, and worthy to rank with the natural yellow mordant colouring matters at present in use (Hummel and Perkin, J. Soc. Chem. Ind., 1895, 14, 458).